Each of network devices connected to local area networks is identified by a network device address (hereafter “network address”) specific to a protocol for the corresponding network to be operated and managed. Identification of individual devices on the networks is made by using the network addresses for the devices to enable the devices to be controlled by a host computer and to exchange data with other network devices on the network.
In a process using the internet protocol (IP), e.g., management of network devices on a network or printing with a printer connected to a network, preliminary assignment of IP addresses effective in the network to the network devices is required.
However, in many of the cases where a network device is connected to a network for the first time (in an initially installed state or the like) or where a network device moved from one network is installed on another network, a network address assigned to a network device before the network device is moved is an invalid address in a network on which the network device is newly installed, because the network segments are changed. In such a case, it is necessary for a user to set a suitable network address for a network device by using a network management software or the like.
In a case where an effective network address is assigned via a network such as a local area network (LAN) from network management software to a network device assigned no effective network address, some network protocol is required for performing communication for assignment. However, the network device assigned no effective network address cannot use any network protocol since the standard network address, e.g., an IP address is not set for it, and cannot use a standard network protocol such as the Simple Network Management Protocol (SNMP).
To solve this problem, network device control methods described below have been proposed.
(1) A network device control method has been proposed in which network management software broadcasts a search packet though a network, and each of a plurality of network devices connected to the network then transmits a reply packet. The network management software receives the reply packet from each network device and displays a list of network addresses (e.g., IP addresses) or physical addresses (e.g., Media Access Control (MAC) addresses), etc., of the network devices found by searching. When a user selects one of the network devices from the list, the network management software sets an input value (e.g., a network address) with respect to the selected network device.(2) A method of automatically setting a suitable network address for a network device has also been proposed in which a network device in a network periodically broadcasts a request for an address, automatic address assignment software executed on a host connected to the network sends back, in response to this request, a reply packet including a suitable network address to the network device, and the network device receives the reply packet and assigns the network address in the reply packet to itself.
In the conventional method (1), however, since a search packet is transmitted to search for network devices, all the network devices replying to the search packet are listed. Therefore, the method has a drawback in that it is difficult for a user to discriminate a network device assigned no network address, i.e., a device to which a network address should be assigned from a plurality of network devices connected to a network.
The conventional method (2) includes the procedure in which a network device itself periodically broadcasts an address request packet and therefore has problems described below. First, the network traffic increases if the number of network devices assigned no network address is increased. Second, it is necessary that automatic network address assignment software be operating on the same network to reply to the address request packet send back a suitable network address as a reply. Third, the method lacks a means for confirming the completion of automatic assignment of a network address. Fourth, it is difficult to reuse an assigned network address after the assigned address has become unnecessary.